<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="lib/vue-2.4.0.js"></script>
</head>
<body>
<div id="app">
    <input type="button" value="toggle" @click="flag = !flag">
    <h3 v-if="flag">这是个H3</h3>
</div>
<script>
    var vm = new Vue({
        el:'#app',
        data:{
            flag:true
        },
        methods:{

        }
    })
</script>
</body>
</html>